Electric heating-pad.



H. E. BLOOMER.

ELECTRIC HEATING PAD.

APPLICATION FILED NOV. 15. m5.

1,215,610. Patented Feb. 13, 1917.

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UNITED STATES PATENT OFFICE.

HARVEY E. BLOOMER, 0F MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO THE SUN-RAY MFG. CO., OF OSHKOSH, WISCONSIN.

ELECTRIC HEATING-PAD.

Application filed November 15, 1915.

To all whom it may concern:

Be it known that I, HARVEY E. BLOOMER, a citizen of the United States,and resident of Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented certain new and useful Improvements in ElectricHeating-Pads; and I do hereby declare that the following is a full,clear, and exact description thereof.

This invention relates to the subject of electric heating pad of thetype that is shown, for example in my allowed application Serial No.860,656 filed Sept. 8, 1914, and the primary aim of the invention is toproduce a heating pad the temperature of which can be regulated toproduce a low, medium or high degree of heat at the will of the user.Another object of the invention is to equip the pad with a thermostaticcontroller that will automatically act to break the circuit in the eventof an excessive current and thereby prevent injury or discomfort to theuser.

A further object of the invention is to produce a heating pad in whichthe cost of production is reduced to the minimum, and in Which simpleyet practical means are provided for preventing short circuiting of theheating current.

Other and further objects of the invention will be apparent from thefollowing detailed description.

One simple embodiment of the improved heating pad is shown in theaccompanying drawings, Wherein Figure 1 is a detail plan View of what Iterm the medium temperature section of the improved heating pad.

Fig. 2 is a similar view of the low temperature section of the pad.

Fig. 3 is a similar view of the thermostatic or dtemperature regulatingsection of the pa Fig. 4 is a sectional view of the pad.

Fig. 5 is a sectional view taken on the line 5-5 Fig. 2.

Fig. 6 is a diagrammatic view of the pad.

Fig. 7 is a view similar to Fig. 5, but illustrating a variation of theinvention.

The improved heating pad is in the form of a blanket, pad, or the like,and it is mainly and preferably formed of flexible material, such ascanvas or other suitable nonconducting material. The heater isSpecification of Letters Patent.

Patented Feb. 13, 1917.

Serial No. 61,709.

preferably formed of three sections, the two outer ones, 1 and 2 beingrespectively the medium temperature section, the low temperaturesection, and the intermediate section 3, which is the thermostatic, ortemperature controlling section.

The medium temperature section 1 and the low temperature section 2 arethe same in structure except the necessary difference in arrangement ofthe coils or convolutions of the conductive wires, each sectionincluding the base or foundation sheet 4 to which the conductive wiresare secured by means of the inclosing tape 5, the tapes being formed ofsuitable non-conductive material and stitched to the sheet 4 in such amanner as to both securely fasten the tape to the sheet and also theconductive wires in proper position for effective heating. It ispreferred, but not essential that the tape 5 be an unbroken length ofmaterial that conforms to the contour of the convolutions of theconductive wires, and at the points where the parallel sections of theconductive wires meet, the sheet 4 has what I term spacing strips 6,formed of suitable nonconducting material stitched to the sheet and tape5. It is noted that the adjacent bends of wire which connect theparallel sections are alternately disposed on opposite sides of therespective spacing strips. The function of this arrangement is thatunder certain conditions considerable shrinkage of the body sectionswould occur which would tend to project the bends of the wire outwardlyof the inclosing tape 5, or other securing means, with a consequentliability of a short circuiting contact, it being understood that inpractical applications of the present structure the parallel wiresections would be disposed closer together and would be relativelylonger than illustrated. By referring more particularly to Figs. 1 and 2of the accompanying drawing, it will be observed that the spacing stripsare so disposed that they overlap each alternate junction of theparallel sections of the conductive wires, and underlap the remainingjunction. By this means the strips 6 efficiently separate and firmlyhold separated, such junctions, so that short circuiting of theconductive wires is prevented.

Various means may be resorted to to obtain the difference in the degreeof heat produced, by selectively controlling circuits each including oneof the two heating sections 1 and 2, and in. the present instance theconductive wires of the section l are disposed closer together than thewires id of section 2, thus procuring" diflering total lengths of wirein the sections The thermostatic, or regulating section 3 is equippedwith suitable thermostatic elements, such for example as of theexpansive type that automatically break the heating circuit in the eventof excessive current, the same being conventionally illustrated in Figs.3 and 6 and designated by the numerals 7 and 8.

The improved pad is diagrannnatically illustrated in Fig. 6 of theaccompanying" drawings, and by i'eterring thereto it will be'observedthat the feed wire G is connected to the condiietive wire B by the mau'ally operable switch 9, and the conductive wire A is suitablyconnected to the teed wire 0 by the manually operated switch 10. its

will be apparentbyopening one of the switches, the heating sectioncontrolled thereby is cutout while the other section will be heated asthe circuit thereof is closed,

Ur, as shown in Fig. 6, by closing both switches, both heater sectionsare placed in circuit with the feed wire, through theircircuitconnection D, thereby imparting heat to both sections with a resultingincrease in the normal temperature of the pad. in any event, the outletfor the heating" current is by the circuit wire E that connects circuitconnector l) with the rheosuat elements 7 and 8, the latterhaving theoutlet or return connection 1F. And as will be obvious, the thermostatwill break the current in the event of an excessive supply ot theheating current, in a manner well understood. I

The heating pad in its finished state is preferably inclosed by jacketii that is wherein the conductive wire "init ate formed oi material thatis impervious to moisture.

Fig. 7 of the accompanying drawings illustrates a variation of theinvention,

insulating material 12, as an additional safeguard and also to add tothe durability of the pad as the insulating medium obviously preventsthe tape and sheet becoming worn through contact with the wire.

it claim:

it, A heating pad comprising a sheet of material, a resistance membersecured to said sheet of material, a second sheet of'mais incased byterial, a second resistance member of lower resistance secured to saidsecond sheet of material, a thirdsheet of materiahthermo stat memberscarried by said third sheet of material, means for securing said sheetstogether, wires extending from the resistance and thermostat members andcorresponding wires of the resistance and thermostat members beingdisposed at adjacent edge portions of the respective sheets.

2., A heating pad including a body sheet of material, resistance wiressecured on the body sheet and bent to procure a series ofparallelstretches, and spacing strips carried by the body strip at theends of said stretches and overlapping alternate adjacent bends of thewire, whereby to prevent contact oi the bends upon shrinkage of the bodysheet, and consequent projection of the bends past the securing means ofthe said stretches of wire.

in testimony that I claim the foregoing l have hereunto set my hand atMilwaukee, in the county of Milwaukee and State of /Visconsin, in thepresence of two witnesses.

Geo. Yonnc, M, 1 3, Downer,

